# $1633. 各赛事的用户注册率
# https://leetcode-cn.com/problems/percentage-of-users-attended-a-contest/

# SQL架构
Create table If Not Exists Users (user_id int, user_name varchar(20));
Create table If Not Exists Register (contest_id int, user_id int);
Truncate table Users;
insert into Users (user_id, user_name) values ('6', 'Alice');
insert into Users (user_id, user_name) values ('2', 'Bob');
insert into Users (user_id, user_name) values ('7', 'Alex');
Truncate table Register;
insert into Register (contest_id, user_id) values ('215', '6');
insert into Register (contest_id, user_id) values ('209', '2');
insert into Register (contest_id, user_id) values ('208', '2');
insert into Register (contest_id, user_id) values ('210', '6');
insert into Register (contest_id, user_id) values ('208', '6');
insert into Register (contest_id, user_id) values ('209', '7');
insert into Register (contest_id, user_id) values ('209', '6');
insert into Register (contest_id, user_id) values ('215', '7');
insert into Register (contest_id, user_id) values ('208', '7');
insert into Register (contest_id, user_id) values ('210', '2');
insert into Register (contest_id, user_id) values ('207', '2');
insert into Register (contest_id, user_id) values ('210', '7');

# Write your MySQL query statement below
select
    contest_id,
    round(
        count(*) / (
            select
                count(*)
            from
                Users
        ) * 100,
        2
    ) as percentage
from
    Register
group by
    contest_id
order by
    percentage desc,
    contest_id;

# clean-up
drop table Users;
drop table Register;